Summer is prime time for home improvements, and many of us hire people to help. But when you let strangers into your home, you may want to take some precautions.

We invite all kinds of people into our homes -- utility workers, contractors, housekeepers, the cable guy. And most of the time, it's no problem, but in some cases, crooks can use these jobs to gain access and information.

History of Home Horrors

In the small town of Franklinton, Louisiana, a 91-year-old woman called a satellite cable company for installation. Cook was the subcontractor dispatched to her home.

"He lay in wait until she got home," Franklinton Police Capt. Justin Brown said. "He spent a large amount of time inside and outside the home. ... He was able to gain the knowledge at that time to be able to come back and commit his crime later."

More than a year after the service call, in January 2010, police said Cook broke through burglar bars and waited for his prey to come home. They said he then tied her up and threatened her until she gave him the pin number to her credit card.

Cook was arrested and charged with five counts, including burglary and kidnapping. He has pleaded not guilty.

In Bergen County, New Jersey, police said Kinga Malkowska, the daughter of a housekeeper, stole jewelry from several homes where her mom worked. Malkowska was arrested. She denied the charges.

In Philadelphia, neighbors said a two-person team posed as water department workers to get inside people's homes. A 90-year-old man said he was tackled to the ground and robbed. The thieves were never caught.

And in perhaps the most famous case of hired help accused of victimizing a homeowner, Brian David Mitchell allegedly kidnapped Elizabeth Smart.

Mitchell knew the family, because Smart's parents had hired him to rake leaves and help fix their roof. Authorities said Mitchell and his estranged wife kept Smart for nine months, until she was spotted by an alert passerby. Mitchell is scheduled for trial in Salt Lake City this November.

Bob Rusbuldt, the president and CEO of the Independent Insurance Agents & Brokers of America, said the No. 1 way to reduce crime in these cases is to never leave a contractor alone in your home.

"You form a bond with these people, and you trust them, but sometimes it's a false trust," he said. "Sometimes these people are in your house for weeks, maybe months. But these are not family members. They are contractors."

Rusbuldt said heavy summer rains and their aftermath create the perfect storm for some contractors who may want to capitalize on your catastrophe.

"Contractors come out of the woodwork. And some people hire them on the spot, which is the exact wrong thing to do. Don't jump at the first contractor who knocks on your door," he said.

Aggressive contractors who go door to door could be scammers -- or worse.

"When a situation like this happens, it takes away their security," Brown said.

In other words, the wrong worker could take not only your money but your sense of safety.

Tips: Keep Your Home Safe From Work Scammers

OK, so what can you do? First of all, never hire anyone in the first place without checking their references.

And make sure contractors are properly licensed and insured in your area -- not another state. A company with an
up-to-date license won't want to risk losing it by sending shady workers who steal from you.

Nevertheless, don't leave your valuables out. Put the jewelry away.

And don't leave temporary workers alone in your home. Follow them from room to room, so they don't have a chance to scope things out.

Avoid giving out your house key, but if you have to -- for example, to a housekeeper -- change your locks when that employee no longer works for you. That might be costly, but it could save you heartache later on.

And finally, tell your neighbors when the job is complete. Let them know they should no longer expect to see any contractor vehicles, or workers around your home.

Web Extra: More Tips for Your Security

The following additional tips for helping keep your home secure were provided to "Good Morning America" by the Independent Insurance Agents & Brokers of America. CLICK HERE to visit the group's website.

Ask any contractors to show you their certificate of insurance before they begin work in your home. Verify its authenticity by contacting the agent listed to check out the coverage. Make sure the contractor is licensed and insured in your jurisdiction.

Never hire anyone without asking for references, and then follow up by contacting the references. Talk to former clients and ask questions not only about the quality of work but also about the demeanor and professionalism of the worker and any other on-site staff.

Hire only firms that have done most of their work in your immediate area. Beware of contractors and companies who are new to the region or do most of their work elsewhere. They are harder to contact and keep track of after a job has been completed.

Always ask who the job supervisor is and how frequently that person will be on your property. Be wary of hiring a firm at which the supervisor has little involvement or time on your premises. Stay in close contact with that person throughout the job.

Remember to handle all payments and transactions professionally. You do not want to become entangled in a dispute that creates resentment and a desire for retaliation on the part of your contractor. Always try to wrap up the project on a positive note.

And, of course, make sure your homeowners insurance policy is adequate and up-to-date, so that if you do incur a loss, you will be covered. Always check in with your agent after you have done major home remodeling, renovation or construction. These types of jobs frequently increase the value of your home, and you will want to adjust your insurance coverage accordingly so that you remain fully protected.